Climate change & extreme weather events

It’s springtime – the time of year for a fresh start. A fresh start to our climate action, that is! If you’re like me and became overwhelmed and disappointed after the results of COP 27 (learn more about what that is here), then the winter was a much needed break from reality. But I always find my motivation returns with the spring – it’s a chance to face goals or challenges with refreshed energy. For me and my climate advocacy, it’s a time to refocus my energy to ensure I am using my skills in effective ways – in ways that will advance our collective desire to stop climate warming.

And that means continuing to write these blog posts for you! Writing and teaching are two of my passions, so I’ve combined them here to try to increase the public’s awareness of the impacts and science of climate change. For me, it also means refocusing the way I use my social media platforms to ensure I am upholding my desire to communicate climate change and conservation science effectively, as well as continuing to pursue research contracts that incorporate climate change. For others in this space, it may mean continuing to strike each week for Fridays for Future or showing up for the climate in other ways. If you are brand new to climate action, it may mean educating yourself on the topic of climate change. And if that’s you, I’m so happy you’ve found my blog. Welcome!

Me doing a public presentation on the topic of climate change at the Osoyoos Desert Centre in August 2022.

My blog posts are cited with trustworthy, publicly available material so that you can see where the information is coming from. To learn about what is causing climate change and how we know it is occurring, read my most recent blog post here. In this post, however, I will discuss extreme weather events and how climate change is increasing the frequency and intensity of them.

I can start this explanation most easily with an analogy – pretend it is the hottest part of summer and you are sitting outside on your patio with friends and a glass of water. The conversation is flowing with the people around you and you forget to take a sip for over an hour. When you go to grab your glass, you notice that there is less water in it than when you poured it… What happened?

Evaporation happened! Remember grade school science and learning about how liquids turn to gas at certain temperatures1? Well, this process is being exacerbated by climate change2. With higher temperatures comes more water vapour in the atmosphere in general3. And when we have more water vapour in our atmosphere, we start to see an increase in things like extreme rain events, storms, flooding, and hurricanes2-4. It can also increase drought – this evaporation will intensify everywhere, but the places that don’t regularly get precipitation will likely continue this trend, thereby creating even drier conditions3-4. More water vapour = more rain where there is rain and less water where it’s normally dry. It’s a simple equation. Unfortunately, more water vapour in our atmosphere also means more warming5. Water vapour is a greenhouse gas, so when there’s more in the atmosphere because of a warming climate, this actually causes the atmosphere to become even warmer5. It’s a positive feedback loop.

The water cycle. Image retrieved from the National Oceanic and Atmospheric Administration.

But what about extreme cold snaps?

Mid-December, I returned from a 5-week trip in Costa Rica to a rare cold snap. In about 24 hours I unexpectedly experienced an almost 50°C change in temperature and my apartment heat decided to stop working. I say unexpected because where I live, in southern interior British Columbia (Canada), temperatures of -20°C mid-December are quite rare6. But it wasn’t just cold where I live – the rest of Canada and the entirety of the United States saw these cold temperatures in December as well7.

Climate change deniers often like to use extreme cold snaps as an example of how the earth is not warming8. But it makes sense that we are seeing these types of events more often, and that climate change is causing them, as long as you understand the science of it.

High above the North Pole is the polar vortex, a mass of extremely cold wind7,9. This cold air is contained within higher latitudes by the polar jet stream, a mass of air closer to the surface of the Earth that moves from west to east around the globe7,9. This jet stream is held strong by Earth’s rotation and the natural (and normal) difference in temperatures between the north and mid-latitudes7,9 – in other words, if the north stays cold and the mid-latitudes stay relatively warmer, the jet stream remains stable, keeping the cold air of the polar vortex above the North Pole where it belongs.

Climate change has been causing the Arctic to warm10. What was once a clear delineation of cold Arctic temperatures and not-as-cold mid-latitude temperatures split by the jet stream, has become two areas with less of a stark difference in temperature. Without the extreme temperature difference, the jet stream weakens, which causes it to flow in a wavy pattern rather than straight across the globe9. This wavy pattern pulls the cold air from the polar vortex down to lower latitudes9, causing the “Arctic front” we saw across news headlines in December. It also drives warmer air up into the Arctic11, which can cause melting and warming that likely exacerbates the problem.

The polar vortex & jet stream. Image retrieved from the National Oceanic and Atmospheric Administration via UC Davis: Science & Climate.

We have not been studying the polar vortex or jet stream long enough to truly understand long term trends that may indicate whether or not these variations in the jet stream are occurring more frequently11. Regardless, we do know that a warmer Arctic causes a weakening of the jet stream and the pulling of cold Arctic air to locations farther south. Whether or not we will see these trends more often because of climate change, I’m not so sure I want to find out.

As always, don’t just trust my word. Below are resources where you can learn more. None of the sources I have included are peer-reviewed literature. Instead, I have curated an assortment of publicly-available reliable sources from some of the world’s leading scientific organizations. Not all important information is hidden in university libraries – these organizations work hard to get this information out there for the public’s best interest. Please read it for yourself.

  1. National Geographic. (n.d.). Evaporation.
  2. NASA. (n.d.). How does climate change affect precipitation?
  3. Columbia Climate School. (2019). How climate change impacts our water.
  4. University Corporation for Atmospheric Research. (n.d.). The water cycle and climate change.
  5. NASA Climate. (2022). Steamy relationships: How atmospheric water vapor amplifies Earth’s greenhouse effect.
  6. Global News. (2022). 34 BC weather records shatter under arctic chill.
  7. NASA Earth Observatory. (2023). Weather whiplash.
  8. Meyer, R. (2019). In The Atlantic. There’s snow on TV, so Trump’s tweeting about climate change.
  9. UC Davis. (2021). Climate change terms and definitions: Polar Vortex.
  10. World Wildlife Foundation. (n.d.). Climate change: How does the climate crisis threaten the Arctic?
  11. National Oceanic and Atmospheric Administration. (2021). Understanding the Arctic polar vortex.

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